4.2 low voltage directive assessment

7/29/2019 4.2 Low Voltage Directive Assessment

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Records of assessment to standards

Customer:Product/Process:Document Owner:Project or Organization Role:Date of manufacture:


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Introduction

BS EN 60204-1 Electrical Equipment

This standard provides requirements and recommendations relating

to the electrical equipment of machines so as to promote:

safety of persons and property

consistency of control response

ease of maintenance.

Part 1 of BS EN 60204 applies to the application of electrical andelectronic equipment and systems to machines not portable by handwhile working, including a group of machines working together in aco-ordinated manner but excluding higher level systems aspects

(i.e. communications between systems).

The equipment covered by this standard commences at the point ofconnection of the supply to the electrical equipment of themachine. Part 1 of BS EN 60204 is applicable to the electricalequipment or parts of the electrical equipment that operate withnominal supply voltages not exceeding 1,000 V for alternatingcurrent and not exceeding 1,500 V for direct current, and withnominal frequencies not exceeding 200 Hz.

Complying with this standard is deemed to meet the essentialrequirements of the low voltage directive. The following list is acheck list that shows that this machine/control system meets therequirements of this standard:


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Power supply

Requirement Compliance

single source;

additional supply derived from devices (transformer);

supply conductor connected to supply disconnector

neutral conductor should not be used;

no connection between neutral conductor and earth;

all terminals clearly marked.

External protective conductor terminal


terminal in vicinity of associated phase terminals;

appropriate size;

terminal marked with PE or grounding symbol


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Supply Disconnector


hand operated

for each incoming supply

when two or more provided, interlock required

either; switch disconnect or, circuit breaker

capable of being locked in off position

one ON and one OFF position, clearly marked

visible gap or position indicator

external operating handle, not red unless E Stop

black lightning sign

easily accessible 0.6 to 1.9 m above servicing level.


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Protection against direct contact


Enclosures must use a key

live parts protected to at least IP1X or IP XXA;

parts intended to be touched while connected requireIP2X or IPXXB;

opening enclosure disconnects supply

Parts that are still live when enclosure is opened must

be protected to IP 2X or IP XXB and so marked; or ifthe disconnector is not door interlocked, all live partsrequire IP2X or IPXXB.

Protection by insulation of live parts


live parts completely covered with insulation,


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Protection against indirect contact


Protection by automatic disconnection of supply

connection of exposed conductive parts to PBC, anduse of protective device;

coordination between supply and protective device

use of switchgear having total insulation

application of supplementary insultation

Protection by electrical separation


Protection by the use of PELV max nominal voltage 25Vac, or 6OV dc

max current in case of failure 1A ac or 0.2A dc

only indoors in dry conditions

source of supply and live ports separated or isolatedfrom circuits with higher voltages

connected to protective bonding conductor associatedwith higher voltage


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Protection of equipment


all conductors except earthed neutral contain devicesto detect and interrupt

neutral conductors with cross sectional area equal tophase conductor

current carrying capacity is of conductors is at leastequal to that required for the load

conductors directly connected to supply and circuitsfeeding control circuit transformers,

Transformers shall be protected in accordance with IEC76-5 and EN60742 as appropriate

avoid nuisance tripping due to transformermagnetizing; avoid excessive winding temperature

Socket Outlets required for circuits feedingmaintenance equipment

each connecting conductor to the protection device isno longer than 3m;

Fuses or setting current as low as possible butadequate for anticipated over current.

Conductors protected in duct.

Overload protection of motors


Motors 0.5kW normally in continuous operationprotection by overload protection devices;

temperature sensing devices

current limitation (inverter driven motors)

Auto restarting shall be prevented unless no risk


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Equipotential Bonding Circuit


PE terminal;

conductive structural parts of electrical equipment andmachine; all exposed conductive parts bonded to PBC

protective conductors in equipment of machine

identified, shape, location, marking, colour

Copper wires preferred.

resistance of any part not allow hazardous current

adequate connection/bonding appropriate termination,type and size;

metal conduits and metallic sheaths, not used as PCSbut must be connected to PBC;

appropriate lids and enclosure doors shall be protectedby PBC provided for purpose

where doors, lids etc are part removed PBC must notbe interrupted

connections must be secure from accidental loosening


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Conductors & Cables

Requirement

generally Copper

Insulation appropriate for use (e.g. fire, toxic fumefrom PVC):

adequate dielectric strength @ 50V ac or 12OV dc testV : 2000V ac for 5 min PELV, 500~ ac for 5 min;

Cables have adequate mechanical strength

Adequate insulation thickness

Current carrying capacity in normal service

Voltage Drop not exceed 5% of nominal voltage

Wiring Practices secure against accidental loosening

Terminals suitable connection for csa of cables used

more than one conductor per terminal ok if designedfor that purpose

terminals on terminal blocks identified, as per circuitdiagram;

shielded conductors properly terminated

ID tags clear and appropriate for environment

terminal blocks mounted and wired to prevent crossingpotentials wires (ie. Terminal barriers end stops etc)

conductors identifiable at each termination

protective conductor shall be readily identified colour

(Green/Yellow)identification of neutral conductor: YeSl if ID by colour = Light Blue

. identification of other conductors l Black: at and dcPower circuits

identification of other conductors Red: ac controlcircuits

identification of other conductors Blue: dc controlcircuits

identification of other conductors Orange: interlock

control circuits supplied from Y?Sexternal power source.


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insulation not available in required colours where multiconductor cable is used.

Visual & Functional Testing


Testing Continuity of PBC

Insulation Resistance

Voltage test (Flash Test)

protection against residual voltage

Electromagnetic Tests

Functional Tests - Starting

Functional Tests - Stopping

Emergency stop located at workstations

Emergency stop colour and background

Emergency stop hardwired and to BS EN 418:1992category 3

Emergency stop removes power to actuators, PLCoutputs and dumps stored energy (pneumatic)


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Control & Signalling Devices


Indicators and buttons

red - emergency

yellow - cautionary

green - normal operation

blue - mandatory intervention

black - stop

white - start

4.2 low voltage directive assessment

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